1. Field of the Invention
The present invention relates to mobile communication and particularly to relocation of user equipment (UE) in Home NodeB (HNB) communication system.
2. Description of the Related Art
Conventionally, relocation is triggered by a UE measurement report. A radio network controller (RNC) determines whether or not to perform a handover or relocation based on analysis of the UE measurement report.
In a HNB system, the analysis of the UE measurement report is handled by the HNB. In a typical relocation procedure which is generally referred to as Outband Handover, a UE is relocated from a HNB to a macro NodeB.
In today's HNB system, application scenarios in which a user is relocated increase due to the increase in Home NodeB Gateway (HGW) and lu-h interface. In addition to the conventional relocation triggered by a UE measurement report, there is a need for a relocation which is triggered by a HGW and performed in cooperation with the HNB. For example:
1) When the HGW is reset, it is necessary to inform the HNB to reselect another HGW and relocate an existing user to a macro NodeB or another HNB which is capable of accept the user.
2) When the HGW detects a severe degradation on uplink service quality in the lu-h interface, it is necessary to improve the existing process to trigger the HNB to initiate a relocation process for the call of the user.
3) When a user who is currently being serviced is removed from the access control list by the administrator, the user can be relocated to a macro NodeB.
Therefore, in the existing lu-h or lu interface, there is no user relocation procedure initiated by an upper layer node.